Chapter 8. Shooting Trouble with Frame Relay

Frame Relay is a Layer 2 edge technology whereby frames travel from your routers (DTE devices) through a series of Frame Relay switches to get to the proper destination. At the edge of enterprise and service provider networks, these switches are DCE devices, although this varies within the clouds. Frame is one of those technologies that is not only available in the United States, but also worldwide. The service can be carrier provided or privately owned and is a cost-effective alternative to leased lines.

This chapter begins the WAN focus of this book with shooting Frame Relay troubles. It gives practical application to a number of objectives falling under the CCNP support guidelines and more. Use familiar Cisco commands and problem isolation techniques to build the chapter scenarios and resolve the Trouble Tickets. This chapter assumes you have a good understanding of protocol characteristics and a methodical troubleshooting mindset.

With supporting the WAN, many times the battle is deciding whether the problem is in fact yours or whether it is a service provider issue. You will analyze real-world Frame Relay issues including Layer 2 and Layer 3 addressing and issues related to LMI, data-link connection identifier (DLCI) assignments, mapping statements, routing protocols, and so on. Continue to identify targets and document the results using ping, trace, show, clear, debug, and other troubleshooting commands and utilities. To gain practical experience, you may follow the many figures and examples in this chapter or use my guidelines to build it yourself.

This chapter covers the following topics:

• Scenario: Shooting Trouble with Frame Relay

• A Brief History of Frame Relay

• Frame Relay Frames

• Frame Relay Addressing

• Frame Relay at the Physical Layer

• Shooting Trouble with Frame Relay

• Trouble Tickets

• Trouble Ticket Solutions